Aircraft components are currently assembled in large holding tools or fixtures. Such tools are substantially rigid and are usually fixed to a factory floor. The holding tools support the aircraft components and provide limited movement capability to slide components together. In large-scale airframe assembly, it is typically assumed that if the holding tool is in the correct position, then the point on the aircraft component where the tool touches or supports the aircraft component will be known, and hence all coordinates on the component are known, and thus, the airframe assembly is correct and the aircraft will meet its aerodynamic requirements.
To ensure proper assembly of the aircraft components, the holding tools typically require periodic measurements (surveying) to ensure that the holding tool is in proper alignment for its specialized task. For example, the airframe support and alignment tools are typically measured for proper position prior to loading of an airframe component. Once the tool measurements are taken and analyzed as within tolerance, the large tooling structures are loaded with the aircraft components and used to move and align said aircraft components. It is presumed that if the holding tools meet their alignment requirements that the aircraft components will also meet design alignment requirements.
Although desirable results have been achieved using such prior art methods, there is room for improvement. For example, large components may deviate from their nominal design due to their complexity and non-uniform material properties. Although a holding tool may be perfect, the assumptions for the component it holds may deviate slightly, though within design specifications, from nominal. These abnormalities may slightly reduce fuel efficiency and may increase manufacturing flow time if trim needs to be corrected. In addition, in many assembly situations measurement technologies are not available to verify that the above-noted assumptions are correct as early in the assembly process as desirable to make needed corrections. Existing measurement technologies are often too expensive or overly intrusive to the assembly process to adequately address this issue. Furthermore, because of the cost and unique design of each holding tool, changes to the aircraft that require tool modifications are typically quite expensive and time consuming. Therefore, novel methods and systems that non-intrusively and economically provide measurements during various stages of the large-scale airframe assembly process would be highly useful.